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H Cohen

Publications and source records attributed to H Cohen.

At least 145 records · Page 8Linked to original sources
PubMed1999

[Ethical dilemmas in gastroenterology practice in Latin-American countries: the AIGE survey].

A survey sponsored by the Interamerican Association of Gastroenterology (AIGE) related to decision making in conflictive ethical situations in the setting of gastroenterological practice was designed (AJ-JCG). Seven problem-cases with 3 to 5 pre-established and not-excluding answers each, demographic and occupational data were included, by public invitation during 1996-97 AIGE educational activities in La Plata (Argentina), Montevideo (Uruguay) and Santo Domingo (Dominican Republic). Data were inserted in a computerised data base, and chi square, Fischer and Maentel-Henzel tests were used for statistical studies. 118 out of 460 doctors registered to educational activities answered at the survey (25.6%). Mean age was 42 +/- 15 years and 57.6% were male; 48.5% were under 10 years of professional practice and 19.5% were over 20 years. Gastroenterology was the main specialty in 89.8%. Although only 15.2% of participants reported as not having Ethical Committee (EC) in their institutions, the option of consulting was not very frequently selected, except in cases of request about pregnancy interruption in the HCV infected mother (22.9%), inclusion of the young alcoholic cirrhotic man in the waiting list for liver trasplant (17.8%), and the Jehova's Witness conscious patient with bleeding esophageal varices (13.5%). Cases of direct communication to the patient of early colon cancer diagnosis (66.1%), and inclusion of the young end stage alcoholic cirrhotic patient in the waiting list for liver trasplantation (65.2%), had the higher consensus. On the other hand, lower consensus (39%) was seen in the case of variceal bleeding in the encephalopathic Witness of Jehova patient. Differential criterla were observed related to sex: 38% of women versus 14.7% of men (p < 0.01) refuse the interruption of pregnancy to the infected HCV patient because of personal convictions against abortion. In the case of suspected HIV co-infection in the IVD HBsAG + carrier, 46% of women vs. 27.9% of men (p < 0.05) indicate HIV screening test without any explanation to the patient because "he could transmit a fatal disease". In this same case, time from graduation was related to differences in option selection: 80.9% in the group > 20 years of professional exercise asked for patient consent and accepted his decision, versus 52.7 and 27.5% in 0-9 and 10-19 years group respectively (p < 0.05). Usual medical and social worries as communication (truth, informed consent), the autonomic decision of biological death versus the sacrament of life, justice in allocation resources, confidentiality and social concern, abortion, and many other controversies linked to tecno-scientific development, impact the practice of Gastroenterology in latinoamerican countries. However medical answers to ethical dilemmas are not uniform. Although our results ought to be verified by other studies they clearly suggest the needs for systematic incorporation of applicated Ethics in pre and postgraduate Gastroenterology curricula, besides the regular activities of our regional institutions.

Adult↗
PubMed1998

Analysis of heart rate variability in posttraumatic stress disorder patients in response to a trauma-related reminder.

BACKGROUND: Spectral analysis of heart rate variability has recently been shown to be a reliable noninvasive test for quantitative assessment of cardiovascular autonomic regulatory responses, providing a dynamic map of sympathetic and parasympathetic interaction. In a prior study exploring the state of hyperarousal characterizing the posttraumatic stress disorder (PTSD) syndrome, the authors described standardized heart rate analysis carried out in 9 PTSD patients at rest, which demonstrated clear-cut evidence of a baseline autonomic hyperarousal state. METHODS: To examine the dynamics of this hyperarousal state, standardized heart rate analysis was carried out in 9 PTSD patients compared to a matched control group of 9 healthy volunteers. Twenty-minute recordings of electrocardiogram in response to a trauma-related cue as opposed to a resting state were performed and analyzed. The PTSD patients were asked to recount the presumed triggering traumatic event, and the control subjects recounted a significant stressful negative life event. RESULTS: Our results show that, whereas the control subjects demonstrated significant autonomic responses to the stressogenic stimulus supplied by the recounting of a major stressful experience, the PTSD patients demonstrated almost no autonomic response to the recounting of the triggering stressful event. The PTSD patients demonstrated a degree of autonomic dysregulation at rest which was comparable to that seen in the control subjects' reaction to the stress model. CONCLUSIONS: The lack of response to the stress model applied in the study appears to imply that PTSD patients experience so great a degree of autonomic hyperactivation at rest, that they are unable to marshal a further stress response to the recounting of the triggering trauma, as compared to control subjects.

Adult↗
PubMed1998

Inhibition of anxiety in rats by antisense to cholecystokinin precursor protein.

BACKGROUND: Cholecystokinin (CCK) and its analogs generates anxiety in humans and measurable anxiety-like behaviors in rats. CCK receptor blockers have had mixed results as a treatment approach for anxiety disorders. Since CCK is a peptide, we explored another strategy to reduce CCK levels in brain by antisense oligodeoxynucleotide inhibition of DNA transcription or messenger RNA (mRNA) translation for CCK precursor protein. METHODS: Antisense oligodeoxynucleotide complementary to the start coding region of rat CCK-precursor was intracerebroventricularly (icv) infused into rats three times at 24-hour intervals. Control groups received infusions of either a scramble sequence oligodeoxynucleotide or vehicle. On the fourth day, rats were assessed in the elevated plus maze paradigm. RESULTS: Compared to vehicle and scramble sequence oligodeoxynucleotide control, icv CCK-antisense exogenous administration for 3 days significantly diminished anxiety behavior in rats. CONCLUSIONS: Antisense inhibition of CCK-mediated anxiety could have therapeutic potential in human anxiety disorders.

Animals↗
PubMed1998

Language development in children with simple-partial left-hemisphere epilepsy.

The nature of cerebral involvement in the acquisition of language was addressed in this longitudinal study of children with an early diagnosis of epilepsy with simple-partial seizures (SPE) and with epileptogenic foci localized in the left frontal (LF) lobe. Yearly evaluations of six SPE-LF children on tests of linguistic comprehension (pointing, understanding of narrative, and understanding of prepositions) and production (repetition, lexical diversity, and grammatical production) were carried out between the ages of 3 and 8 years and compared to those of large samples of control children on the same tasks and at each age level. Linguistic production of all children were transcribed, coded, and analyzed using the Child Language Data Exchange System (MacWhinney & Snow, 1991). Individual evolution trajectories revealed that SPE-LF children showed a clear dissociation in linguistic performance between comprehension and production. Linguistic comprehension gradually improved to reach normal performance levels by age 7 while linguistic production, even at later stages, remained quite poor. This dissociation in the development of linguistic performance in SPE-LF children suggests a complex interplay between brain maturation dynamics and dysfunction modulating the succession of stages in language development. The observed persistent deficits in specific aspects of linguistic performance argue for an early involvement of the anterior areas of the left cerebral hemisphere in the production of language.

Age Factors↗
PubMed1998

Effect of transcranial magnetic stimulation in posttraumatic stress disorder: a preliminary study.

BACKGROUND: Transcranial magnetic stimulation (TMS) has become, over the last few years, a promising avenue for new research in affective disorders. In this study we have evaluated the clinical effect of slow TMS on posttraumatic stress disorder (PTSD) symptoms. METHODS: Ten PTSD patients were given one session of slow TMS with 30 pulses of 1 m/sec each, 15 to each side of the motor cortex. RESULTS: Symptoms of PTSD were assessed by using three psychological assessment scales, at four different time points. In this first, pilot, open study, TMS was found to be effective in lowering the core symptoms of PTSD: avoidance (as measured by the Impact of Event Scale), anxiety, and somatization (as measured by the Symptom Check List-90). A general clinical improvement was found (as measured by the Clinical Global Impression scale); however, the effect was rather short and transient. CONCLUSIONS: The present study showed TMS to be a safe and tolerable intervention with possibly indications of therapeutic efficacy for PTSD patients.

Adult↗
PubMed1998

Feasibility and pharmacokinetics of carbamazepine oral loading doses.

The pharmacokinetics and adverse effects of an oral loading dose of carbamazepine administered in tablet or suspension form were studied. Patients on a hospital epilepsy unit who were to receive carbamazepine as a discharge medication were randomly assigned to receive either an oral 8-mg/kg loading dose of the tablet formulation or the same dose of the suspension on an empty stomach. Blood samples were drawn before and at intervals up to 12 hours after the loading dose. Adverse effects were evaluated subjectively and objectively. Total and free serum carbamazepine and carbamazepine-10, 11-epoxide (CBZE) concentrations were determined by high-performance liquid chromatography. Six adult patients were enrolled in and completed the study. All the patients achieved therapeutic total carbamazepine levels; the suspension group did so within two hours and the tablet group within five hours. Maximum serum carbamazepine concentrations ranged from 7.10 to 9.92 mg/L, area under the concentration-versus-time curve from 54.85 to 82.23 micrograms.hr/L, and terminal elimination half-life from 14.05 to 15.71 hours. Adverse effects were mild, few, and short-lived; none of the patients developed gastrointestinal toxicity. Adverse effects were not associated with total or free carbamazepine and CBZE concentrations or with total or free CBZE:carbamazepine ratios. An oral loading dose of carbamazepine 8 mg/kg achieved therapeutic levels within two hours when given as a suspension and within five hours when given as tablets and was well tolerated in all patients.

Adult↗
PubMed1998

Dietary sodium intake and mortality: the National Health and Nutrition Examination Survey (NHANES I).

BACKGROUND: Population-wide restriction of dietary sodium has been recommended. However, little evidence directly links sodium intake to morbidity and mortality. The aim of this study was to assess the relation of sodium intake to subsequent all-cause and cardiovascular-disease (CVD) mortality in a general population. METHODS: The first National Health and Nutrition Examination Survey established baseline information during 1971-75 in a representative sample of 20729 US adults (aged 25-75). 11348 underwent medical examination and nutritional examination based on 24 h recall. Two had no data on sodium intake available. Vital status at June 30, 1992, was obtained for the 11346 participants through interview, tracing, and searches of the national death index. Mortality was examined in sex-specific quartiles of sodium intake, calorie intake, and sodium/calorie ratio. Multiple regression analyses were done to assess the relations with mortality. FINDINGS: There were 3923 deaths, of which 1970 were due to CVD. All-cause mortality (per 1000 person-years; adjusted for age and sex) was inversely associated with sex-specific quartiles of sodium intake (lowest to highest quartile 23.18 to 19.01, p<0.0001) and total calorie intake (25.03 to 18.40, p<0.0001) and showed a weak positive association with quartiles of sodium/calorie ratio (20.27 to 21.71, p=0.14). The pattern for CVD mortality was similar (sodium 11.80 to 9.60, p<0.0019; calories 12.80 to 8.94, p<0.0002; sodium/calorie ratio 9.73 to 11.35, p=0.017). In Cox multiple regression analysis, sodium intake was inversely associated with all-cause (p=0.0069) and CVD mortality (p=0.086) and sodium/calorie ratio was directly associated with all-cause (p=0.0004) and CVD mortality (p=0.0056). By contrast, calorie intake in the presence of the two measures of sodium intake was not independently associated with mortality (all-cause p=0.86; CVD p=0.74). Analysis restricted to participants with no history of CVD at baseline gave similar results. INTERPRETATION: This observational study does not justify any particular dietary recommendation. Specifically, these results do not support current recommendations for routine reduction of sodium consumption, nor do they justify advice to increase salt intake or to decrease its concentration in the diet.

Adult↗
PubMed1998

Laser wire for crossing chronic total occlusions: "learning phase" results from the U.S. TOTAL trial. Total Occlusion Trial With Angioplasty by Using a Laser Wire.

The Prima laser guidewire system (Spectranectics Corp., Colorado Springs, CO) consists of an 0.018" hypotube containing a bundle of 45-microm optical fibers coupled to a pulsed excimer laser operating at a tip fluence of 60 ml/mm2 and a repetition rate ranging from 25-40 Hz. This laser guidewire was specifically designed to cross total occlusions refractory to passage with conventional wires. The Prima wire was evaluated in a feasibility study at 15 U.S. centers. Following failure to cross a total occlusion with approved guidewires, the Prima wire was utilized in 179 patients. Average age of subjects was 61 yr. Lesion locations included left anterior descending (36%), right (45%), and circumflex (19%) coronary arteries. Mean angiographic age of total occlusions was 70 wk (range, 2-1,020 wk, median, 14 wk). The use of the Prima wire either solely or in combination with conventional guidewires resulted in successful crossing in 61% of these previously impenetrable occlusions. Failure of the device was commonly related to length of the occlusion and tortuosity along the occluded pathway. Major complications included myocardial infarction in 7 patients (3.9%), tamponade in 3 (1.7%), and death in 2 (1.1%). This "learning phase" pilot study confirmed the feasibility of a laser guidewire in chronic total occlusions that are resistant to passage of conventional guidewires. An extended registry at these investigative sites is planned.

Adult↗
PubMed1998

Identification of mimicry peptides based on sequential motifs of epitopes derived from 65-kDa glutamic acid decarboxylase.

Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease with a predominantly non-hereditary etiology that results in a destruction of pancreatic beta cells by autoaggressive T lymphocytes. Neither the mechanism of initial stimulation of these T cells nor the nature of the environmental factors implicated in the disease have so far been identified. However, both issues are taken into account by the hypothesis of initial T cell activation by viral or bacterial mimicry peptides with sequence similarities to pancreatic self antigens. We determined sequential epitope motifs to search for mimicry peptides stimulating T cell lines specific for two epitopes derived from the IDDM autoantigen 65-kDa glutamic acid decarboxylase (GAD65). These were GAD65 (88-99), presented by HLA-DRB1*0101, and GAD65 (248-257), presented by HLA-DRB5*0101. T cell stimulation by peptides with substitutions in HLA anchor or T cell contact positions was analyzed to establish degenerate epitope motifs for database searching. Out of 28 tested candidate mimicry peptides derived from bacterial, viral and human proteins, 3 stimulated T cell lines and a T cell clone specific for epitope GAD65 (248-257). Our results demonstrate that mono- and polyclonal GAD65-specific T cells from IDDM patients can be stimulated by viral and bacterial peptides with little apparent sequence homology with autoantigenic epitopes. Moreover, in a synopsis with related published studies, our findings suggest that simple degenerate search motifs comprising principal T cell contacts plus HLA class II binding motifs may suffice to identify most mimicry peptides.

Adult↗
PubMed1998

Effect of blood on rapid urease testing of gastric mucosal biopsy specimens.

BACKGROUND: The effect of blood on rapid urease tests is uncertain. We assessed the effect of soaking gastric biopsy specimens in blood on the results of both agar gel (CLOtest) and strip (Pyloritek) rapid urease tests. METHODS: One hundred patients undergoing endoscopy had four adjacent biopsy specimens taken from normal appearing mucosa in the antrum. Two biopsies were soaked in blood for 1 minute; one specimen was placed on a CLOtest and one on a Pyloritek. The other two biopsy specimens were placed on CLOtest and Pyloritek without soaking in blood. The same process was performed with four adjacent biopsy specimens from the gastric body. CLOtests were read at 1, 4, and 24 hours; Pyloritek results were read at 1 hour. RESULTS: The number of positive tests for the blood-soaked and standard biopsy specimens were comparable at all times for both rapid urease tests. Discordant results between the blood-soaked and standard specimens were seen in 17 of 400 test comparisons (4%): in 8 of these only the blood-soaked specimen was positive, and in 9 only the standard specimen was positive. CONCLUSIONS: "Contamination" of biopsy specimens with blood does not alter rapid urease test results.

Biopsy↗
PubMed1998

Epidemiology of risk in hypertensives: experience in treated patients.

Knowledge of the epidemiology of cardiovascular disease (CVD) in hypertensive patients derives primarily from observation of populations composed largely of untreated subjects. Increasingly, however, individuals with elevated blood pressure are treated. An 18-year observational study of 8690 participants in a systematic hypertension control project reveals that cardiovascular events continue to be the principal morbid and mortal outcomes. Over time, the incidence of stroke and heart attack remained stable, whereas congestive heart failure (CHF), as a first event, increased tenfold after 10 years. Diabetes and evidence of vascular disease at entry predicted morbidity. Persisting cardiovascular morbidity in the face of satisfactory blood pressure control suggests the need for additional preventive intervention.

Age Factors↗
PubMed1998

Bisphosphonates and tetracycline: experimental models for their evaluation in calcium-related disorders.

PURPOSE: This work was aimed at synthesizing novel bisphosphonates (BPs) and examining them in comparison to clinically used BPs such as pamidronate and alendronate, and to tetracycline, in order to evaluate their potential as anticalcification and antiresorption agents. The correlation between the various models was examined in order to establish facile experimental models for pre-screening of potential compounds. METHODS: Nitrogen-containing heterocyclic, novel BPs such as 2-(3-methylimidazolio) ethylidene-1,1-bisphosphonic acid betaine (VS-5b), 2-(2-dimethylamino-4-pyrazinio)ethylidene-1,1-bisphosphonic acid betaine (VS-6b), and 2-(2-alpha-pyridylethylthio) ethylidene-1,1-bisphosphonic acid (ISA-225), were synthesized and evaluated in comparison to clinically used BPs, in various experimental models of resorption and calcification. RESULTS: The physicochemical properties of the novel compounds are slightly different than the BPs in clinical use: the pKa values are lower, the affinity for hydroxyapatite is lower and the solubilities of the calcium salts are higher. The anticalcification potencies of the novel compounds were high and ranked as follows: alendronate = pamidronate > VS-6b = VS-5b = ISA-225 > tetracycline. The in vivo antiresorption activity of VS-5b and VS-6b in comparison to that of the clinically employed, pamidronate, was shown to be similar and higher, respectively. CONCLUSIONS: The anticalcification activity of the novel compounds as well as that of tetracycline was lower than that of alendronate. The antiresorption activity of VS-6b was similar to that of pamidronate. A good correlation between the different models was found, enabling the facile screening of novel compounds. The activities of tetracycline and EDTA highlight the distinct behavior of BPs as "crystal poison." In addition, tetracycline was found to be a potent anticalcification agent in the ectopic calcification model.

Alendronate↗